A major part of my comment thesis is that courts don't protect the politically powerless, but rather only intervene once a marginalized group has demonstrated some clout in the political arena. And wouldn't you know it if, fresh on the heels of Judge Walker's historic opinion striking down California's anti-gay marriage constitutional amendment, we see a poll indicating that half of all Americans agree with him.
Of course, my suspicion is that these things aren't independent of each other. High profile gay marriage victories make it more likely that more people will label themselves in support of gay marriage, because the position has moved from fringe to mainstream (and people generally don't like to consider themselves fringe). At the same time, of course, growing popular support for gay marriage is what makes pro-gay marriage rulings feasible -- it's what moves them from "kooky, frivolous argument" to "position I have to take seriously".
I should say that I don't think whether gay marriage is constitutionally protected is dependent on whether a majority wills it so. I just think descriptively, judicial recognition of gay rights (or really any rights claim) seems to move in tandem with popular recognition of the same.